Design Of Three-Axis Positioning Platform For Measuring Points On Circuit Board

With the development of electronic technology,a variety of highly integrated complex electronic systems are emerging constantly,so some higher requirements are put forward in circuit board testing and fault detection.According to the needs of testing,automatic test system has been widely used because of its versatility,high reliability and good scalability,and has been an important means of the new generation of test technology.However,it requires the operator to manually move the test probe to the circuit board point in the testing process,and did not realize the full automation testing,while the precision and accuracy of test are affected because of the operator's repeated labor and low efficiency.In recent years,domestic and foreign began to reaserch the fully automated circuit board automatic test system,in which the mechanical motion platform as an important part also has great significance,so this paper designs a three-axis positioning platform for circuit board testing.The main work and achievements are as follows:1.Combined with the application background of the three-axis positioning platform,this paper put forward a design scheme.The platform is driven by the rotating motor and the mechanical transmission,and the motion control is carried out by the combination of "PC +motion control card" and semi-closed loop control system.Then this paper analyzed and selected the main hardware,including paltforrm body,motor and its driver,motion control card,the limit switch and so on,completed the construction of the whole platform.2.A probe feedback system was designed for the problem that the equipments is easily damaged due to their contact in the testing process,which used the pressure sensor and the HX711 to collect the pressure information and was then received by the STM32 processor and communicated with the PC.It not only improves the motion control of the probe in the Z-axis direction,but also reduces the impact of the probe and ensures the reliable contact between the probe and the circuit board.3.Based on the idea of structured and modular,the platform software is divided into six modules:initialization,motion control,parameter setting,data communication,status display and emergency stop.The function of each module is realized by Visual C#programming language,meanwhile this paper designed a good user interface.4.This paper tested the basic function of the three-axis positioning platform,and applied it to the the circuit board automatic positioning test system to jointly test.The result showed that the platform can meet the requirements of accuracy and the corresponding test tasks.